Cause one: The sealing surface is damaged. At this time, it is necessary to check the damage of the sealing surface, and then to repair the damage after grinding or turning and then grinding, to ensure the flatness of the sealing surface after the repair, and the smoothness of the sealing surface can not be less than 10.
Cause two: Improper installation. It is necessary to reinstall the safety valve and check the additional load to remove the pipe.
Reason 3: Caused by high temperatures. When choosing a safety valve, a suitable safety valve should be selected according to the use environment of different temperatures. In the case of high temperature, a heat-relief valve or other special structure safety valve that can be used in high-temperature medium should be selected, and appropriate heat insulation protection measures must be taken. .
Cause four: The opening pressure is too close to the working pressure of the equipment. Reposition the spring within the pressure range of the spring. If the spring pressure range is exceeded, replace the spring.
Cause five: Entrapment of dirt on the sealing surface. Need to clear the dirt on the sealing surface, first use a wrench or other method to open the valve of the safety valve, remove the dirt, you can blow off the dirt, if you can not blow away, we must open the valve for cleaning.
Some of the plastic variety that people will produce large, low price, wide use and wide influence is called standard plastic.Its connotation often changes with the development of time and science and technology.Important standard plastics are polyethylene, polypropylene, polyvinyl chloride, polystyrene and other varieties
standard plastics including polyethylene, polypropylene, polystyrene, PVC, acrylic - butadiene - styrene), poly (methyl benzene acid methyl ester and amino plastics and so on, its production accounted for more than 90% of the whole plastic production, so it is also called the large plastic varieties.
Merits and demerits
Compared with wood, metal, cement, glass and other materials, standard plastics have the following advantages and disadvantages.
Advantages: (1) easy to form, high degree of freedom of design;(2) easy coloring;(3) stronger than metal;(4) lighter weight;(5) easy to modify, easy to obtain required performance;(6) good electrical insulation;(7) good water resistance and no rust;(8) good chemical resistance;(9) production consumes less energy than metal;(10) as long as the waste plastics are treated well, the environmental damage and pollution will be less than other materials.
Disadvantages: (1) poor weatherability, especially in ultraviolet light, aging easily under uv light;(2) generate static electricity;(3) large thermal expansion coefficient and poor dimensional stability;(4) low surface hardness, easy to produce scratches;(5) poor durability and poor environmental stress cracking.
But with the continuous development of blending technology progress, as well as the standard polymer high-performance achievements, some of its insufficient gradually improved, broadens the application field of Standard Plastic, made of plastic in the position in the national economy more and more important.
Standard plastics has excellent performance, variety and versatility.Standard plastics can replace metal materials, cellulose materials and silicate materials with three traditional materials, and as the most powerful competitor of traditional materials.Standard plastics has been widely used in agriculture, light industry, textiles, electronic appliances, machinery, building materials, packaging and transportation and other departments, profoundly influences the whole development and the progress of science and technology, industrial and agricultural production in social development and national economic development, people's material and cultural living standards improve all aspects such as occupies very important position.
The purpose of standard plastics can be covered in the following aspects:
(1) Agriculture: various kinds of agricultural film, sheet materials, holding irrigation pipes, sprinkling irrigation pipes, fishing nets, breeding boxes, floating materials.
(2) industry: due to the electrical insulation of plastics, standard plastics are already used in the electrical industry to make insulating materials and packaging materials.Manufacturing parts and shells in electronic and instrumentation industries;Transmission gears and bearings in the mechanical industry;Chemical industry of various anti-corrosion containers, pipes, slots, tanks, etc.
(3) construction industry: Plastic doors, Windows, ceilings, floor leather, plumbing and pipe fittings, gas pipes and fittings, etc. are made from traditional materials such as wood and metal.
(4) Packaging: Various woven bags, packaging films, composite films, hollow containers, revolving boxes, corrugated boxes, packaging belts, foam plastics, etc.
(5) daily supplies: all kinds of plastic toys, toothbrushes, soap boxes, raincoats, tableware, utensils, slippers, etc.
(6) medical and equipment industry: all kinds of artificial organs, medical use infusion bags, one injection supplies, degradative medical materials.
(7) electric appliance industry: All kinds of office appliances and household appliances insulation, heat preservation, anticorrosive, moisture-proof housing, resistance to the tang, precise military components and so on.
Divisor in the above areas,standard plastics apply more extensive, at present, some standard plastics by modification to expand the application field, in the defense cutting-edge industry, transportation and aviation industry used as structural materials a lot.
Production:
(b) PP Plastic Sheet
(c)Pmma Plastic Sheet/Acrylic Plastic Sheet /ESD PMMA Plastic Sheet/ESD Acrylic Plastic Sheet
Standard Plastics <80℃
Standard Plastic,PE Plastic,PP Plastic,Acrylic Plastic
Dongguan Noegem Plastic Products Co.,Ltd , http://www.noegempLastic.com